The present invention is directed to a system for supplying electric power to an artificial heart assembly from an external power source.
U.S. Pat. No. 5,674,281 to Snyder discloses an artificial heart assembly having a blood inlet conduit, a blood outlet conduit, and a pumping mechanism that pumps blood from the blood inlet conduit to the blood outlet conduit. The Snyder artificial heart assembly includes a first membrane defining a blood chamber fluidly coupled to the blood inlet conduit and the blood outlet conduit, and the pumping mechanism includes a pusher plate that makes contact with the first membrane to force blood from the blood inlet conduit to the blood outlet conduit. The Snyder artificial heart assembly also has a second membrane defining a second blood chamber fluidly coupled to a second blood inlet conduit and a second blood outlet conduit and a second pusher plate that makes contact with the second membrane to force blood from the second blood inlet conduit to the second blood outlet conduit.
U.S. Pat. No. 5,728,154 to Crossett, et al. discloses an artificial heart assembly that has a structure similar to the artificial heart assembly described above in connection with the Snyder patent. The Crossett, et al. patent also discloses a communications system that includes an external transceiver located external of a subject and an internal transceiver that is implanted beneath the skin of a subject. The internal transceiver is provided with an internal coil.
U.S. Pat. No. 5,751,125 to Weiss discloses an artificial heart assembly, which is provided either as a total artificial heart or as a ventricular assist device, having a sensorless motor and a circuit for reversibly driving the sensorless motor.
U.S. Pat. No. 5,630,836 to Prem, et al. discloses a transcutaneous energy and data transmission apparatus for a cardiac assist device such as an artificial heart or ventricular assist device. The transmission apparatus has an external coupler in the form of a tuned circuit with an induction coil and an internal coupler which together act as an air-core transformer. The transmission apparatus has a DC power supply and a power converter that are coupled to the external coupler. The power converter converts electric current from the DC power supply into high-frequency AC. The transmission apparatus has a Voltage regulator coupled to the internal coupler. As shown in FIG. 3 and described in connection therewith, the Prem, et al. patent discloses that the voltage regulator includes a shunt switch and a shunt controller. As shown in FIG. 2, the power converter includes an H-bridge inverter, an H-bridge controller, and a shunt detector. The H-bridge controller can reduce the duty cycle of the H-bridge converter if a shunt is detected.
In one aspect, the invention-is directed to an apparatus adapted to be used in connection with an artificial heart assembly having a blood inlet conduit, a blood outlet conduit, and a pump that pumps blood from the blood inlet conduit to the blood outlet conduit. The apparatus includes an internal coil adapted to be implanted beneath the skin of a subject, an AC-to-DC converter that provides electric power from the internal coil to the pump, an external coil adapted to be disposed adjacent the internal coil and separated from the internal coil by the skin of a subject, the external coil being coupled to transmit electric power to the internal coil through the skin of the subject. A DC-to-AC converter is coupled to the external coil and to a source of DC power. The DC-to-AC converter selectively converts DC power from the DC power source into either a first frequency during a first period of time or a second frequency during a second period of time, the first frequency being different than the second frequency.
The invention is also directed to a method of supplying electric power to an artificial heart assembly having a blood inlet conduit, a blood outlet conduit, a pump that pumps blood from the blood inlet conduit to the blood outlet conduit, and a motor that drives the pump. The method includes: generating an AC electric current from a DC voltage, causing the AC electric current to flow through an external coil disposed adjacent the skin of a subject to induce AC electric current through an internal coil disposed beneath the skin of a subject, rectifying the AC electric current through the internal coil to generate a DC voltage, supplying the DC voltage to the motor, and changing the frequency of the AC electric current based on whether the magnitude of the DC voltage is greater than or less than a threshold value.
The features and advantages of the present invention will be apparent to those of ordinary skill in the art in view of the detailed description of the preferred embodiment, which is made with reference to the drawings, a brief description of which is provided below.